1. Field of the Invention
The present invention relates to an antenna unit to be incorporated into a door handle of a vehicle and a door handle device including the antenna unit.
2. Description of the Related Art
A smart entry system for enhancing the convenience in opening and closing operations of a vehicle door has recently been developed and already put in practical use. In the smart entry system, a driver who carries an electronic key incorporating a wireless device for transmitting an ID signal has only to approach or leave a vehicle for locking or unlocking a door locking device of a vehicle.
A door handle device for vehicle employing such a smart entry system is provided with: an antenna configured to transmit and receive an ID signal and the like; and a capacitive sensor (a touch sensor) configured to detect the driver's approaching or touching a door handle. When the driver carrying the electronic key touches the door handle to open the door, the capacitive sensor incorporated into the door handle detects the touch, and an authentication device of the vehicle transmits a request signal to the electronic key through an antenna. The electronic key having received the request signal transmits an ID signal including an ID code of the key to the authentication device of the vehicle. If the ID code in the received ID signal matches an ID code stored in advance, the authentication device of the vehicle having received the ID signal authenticates the electronic key and drives an actuator of the door locking device, so that the door locking device enters an unlock state in which the door is openable.
Meanwhile, Japanese Patent Application Publication No. 2003-224410 has made a proposal to enhance assembly workability by simplifying handling of an antenna while protecting the antenna. Specifically, an antenna and a detection electrode of the capacitive sensor which are provided in a door handle are integrally molded with a synthetic resin for molding.